Tubular elastic fabric and process of making same



July 2, 1940. R. E. DAVIS 2,206,808

TUBULAR ELASTIC FABRIC AND PROCESS OF MAKING SAME.

Filed Sept. 15, 1938 2 Sheets-Sheet l HHH E July 2, 1940. R. E. DAVIS2,206,803

TUBULAR ELASTIC FABRIC AND PROCESS OF MAKING SAME Filed Sept. 15, 1938 2Sheets-Sheet 2 Patented July 2, 1940 UNITED STATES PATENT OFFICETUBULAR. ELASTIC FABaIc AND raocnss or MAKING SAME Application September15, 1938, Serial No. 230,121

'1 Claims.

This invention relates to knitted fabrics having elastic yarnincorporated in predetermined courses of the stitches of which thefabric is composed. The invention particularly relates to ribbed fabricswith rubber, bare or covered, laid in successive or relatively spacedstitch courses between the stitch wales on one face of the fabric andthe stitch wales on the opposite face thereof. The invention in itsbroader'aspects'however is applicable to the knitting of non-ribbedfabrics,

Knitted fabrics having rubber incorporated in the stitch coursescontracts excessively in a coursewise direction, due to the fact that indrawing the rubber from its supply, such as a spool etc., the rubber isunavoidably placed under tension and is stretched thereby prior to, as,and when it is being incorporated in the fabric.

When knitted fabric is released from the knitting needles it inherentlycontracts to some extent when there is no rubber incorporated therein,but, when the fabric contains rubber yarn, the tension on the rubber isreleased with the knitting tension of the fabric and immediatelycontracts with and to a greater extent than the normal contraction ofthe fabric. This causes the fabric to be abnormally contracted.

Complicated and expensive laying-in and other rubber feeding attachmentshave been devised for feeding rubber into knitted fabrics under zerotension which have functioned with various degrees of success but whichat the best have required constant attention to maintain in adjustment.

Manufacturers of hosiery and other tubular knitted structures in orderto obtain anormally sized finished product, such as a stocking top forexample, which would ordinarily be made on a three and one-half inchdiameter machine and which if the fabric containedno rubber wouldnormally contract to say about a two and onehalf inch diameter, butwhich when rubber is incorporated therein contracts to about a one andone-half inch diameter, have resorted to knitting the fabric on amachine of about a five inch diameter. Such a machine will produce afinished rubber-containing fabric of a normal two and one-half inchdiameter. These figures are here given for the purpose of comparativeillustration only and are not intended to represent any accuratelycalibrated actual examples.

The object of the present invention is to pro-- vide a simple processand inexpensive apparatus for laying rubber in knitted fabric or forfeeding it to incorporating mechanism under positive zero or lighttension, or, if desired, under longitudinal compression whereby, withthe former, the fabric, after knitting, may contract only to itsnormally inherent extent, or, with the latter, the fabric may retainapproximately the same size it obtained during knitting or be expandedcoursewise, i. e. the coursewise dimension corresponding to the overalllength of the needle bed or circumference of the cylinder and/or dialmay be retained in the fabric with the stitch wales spaced apartlaterally to the same extent as the needles, or the coursewisedimensionof the fabric and the lateral spacing of the wales may be decreased, orincreased, depending upon the adjustment of the simple mechanism formingthe basis of the present invention.

In the accompanying drawings:

Fig. 1 diagrammatically illustrates a swatch of ribbed fabric withrubber laid. in successive courses thereof in accordance with the mind--ples of the present invention;

Fig. 2 diagrammatically illustrates, in plan, the cylinder and dial ofa, circular rib knitting machine equipped to produce the fabric of Fig.1;

Fig. 3 diagrammatically illustrates a linear development of a portion ofthe cylinder and dial with the needles thereof being manipulated inaccordance with the principles of the present invention to produce thefabric of-Fig. 1; and

Fig. 4 diagrammatically illustrates the cam ring and path of the buttsof the cylinder needles for actuating the cylinder needles in the mannerindicated in Fig. 3.

As shown in Fig. 1 the fabric F consists of successively interknitcourses cl, c2, c3, c4, 05, etc. of stitches s and -sl respectivelyforming wales w and wl on opposite faces respectively of'the fabric.

In the present illustration, Fig. 1, there is a rubber strand R inlaidin each of the stitch courses. It will be understood that this is theresult of using a' single feed circular machine such as disclosed inFigs. 2, 3 and 4 of the drawing. However, if a multiple feed machine isused there may be a rubber inlaying finger, tube, eye, etc., at each orat any desired number of such feeds, in which case the rubber R would belaid in each course or in as many relatively spaced courses as therewould be rubber feeds adjacent thread feeds. For example, in a two feedmachine with a rubber feed at only one thread feed the rubber R would belaid in only every alternate course, or in every third course in a threefeed machine provided with a rubber feed at only one thread feed, and soon.

As shown in Figs. 2 and 3, a needle cylinder III with needles I in thegrooves l2 thereof cooperates with a dial having needles 2| operating inthe grooves 22 thereof.

The cylinder needles I occupy the normal rest or tuck position with thebutts l3 thereof resting on a rest cam l4 in the cam ring, as shown inFig. 4. These needles would be ordinarily raised to clearing position bya clearing cam I6. At the "high position, the needles would take theknitting yarn Y in their hooks ll whereupon the needles would be loweredto casting position by the usual stitch cam l8, to form the stitches sof the wales w.

or confined in a suitable container.

The dial needles would be actuated in the usual manner to take theknitting yarn Y in their hooks 23 from between adjacent cylinder needlesI! as the latter descended in their respective grooves l2 and would beprojected previously thereto and retracted concurrently with the'descentof the cylinder needles by the usual cams carried by the dial cap 24,shown in plan in Fig. 2. These cams being usual and no variation in thenormal travel of the dial needles being required in carrying out thepresent invention, the dial needles cams in the cap 24 have beeneliminated from the drawings.

In carrying out the present invention the rubber yarn R is fed to themachine at some distance ahead of the feeding of the knitting yarn Ytothe needles, as shown in Fig. 2, while the cylinder needles are at restwith their hooks above the top edge H! of the cylinder ID.

The rubber R may be drawn from any suitable source such as a spool,bobbin or other package or from a loose pile lying on a suitable supportNo heed need be paid to the degree of tension on the strand R or thelack of tension, beyond assuring that the rubber is running freely andwith a fair amount of uniformity to the needles.

The rubber strand R is fed to the cylinder needles against the outerfaces 9 thereof below the hooks I1 and above the upper edge H of thecylinder l0. Due to the curvature of the cylinder the rubber R bearsagainst the outer faces 9 of the needles II, and is laid on the top edgeIQ of the cylinder, in a segment or sector R, radially beyond andconcentric to the circle of the fabric F where it forms against orbetween the inner surface of the cylinder I0 and the outer peripheraledge of the dial 20, thus the arc of the rubber strand segment RI is ofgreater radius than the fabric circle, thus, a complete circle of rubberis of greater diameter than the diameter of the knitting circle of thefabric and if laid in the fabric with zero tension the rubber will tendto retain the fabric at its knitting diameter or tend to increase beyondits knitting diameter.

Normally in laying rubber in ribbed fabrics it is laid behind thecylinder needles and against the peripheral edge of the dial, which atthe outset makes the diameter of a circle of the rubber, at zerotension, less than the knitting diameter of the fabric.

In order to insure zero tension on the rubber R or in order to place therubber under longitudinal compression within the fabric, according tothe present-inventiomthe rubber is drawn ,,down in successive loops orfestoons L into the tops of the cylinder needle grooves .l2 by theneedle hooks I! of the needles around the tbps 8 of the ribs orpartitions l which are formed between adjacent needle grooves 2, asclearly shown at R2 in Figs. 2 and 3.

Where the rubber is first engaged by the hook of a needle and pulleddown into a groove l2 the rubber is placed thereby under tension andthis tension reacts to draw rubber from the supply. The depth to whichthe rubber is drawn into the top of the groove, 1. e. the length of eachloop L, controls the degree of tension placed on the rubber and this inturn controls the amount of rubber drawn from the supply.

In order to keep the initial tension from reacting in the oppositedirection to withdraw the rubber from the fabric a plurality of theloops L of the rubber are held down in a number of adjacent needlegrooves, which snubs the rubber and prevents it from moving one way oranother within the sector R2, which may be termed the holding sector.

The needles are lowered to the desired extent in the grooves |2 to drawthe desired amount of rubber from the supply, by a draw cam 25, theintroduction of which into the cam ring con stitutes practically theonly change that is required to be .made in a normal machine in order towork the method of the present invention.

If desired, a lift cam 26 may be introduced ahead of the draw cam 25 tolift the needles slightly to insure the rubber passing below the hooksll of the needles. This, however, in some instances at least, may beeliminated.

At the distant end of the holding sector R2 the needles H are raised bythe ordinary clearing cam Hi. The raisingof the needles slacks thetension on the rubber R before it is laid in the fabric, consequently,in the sector R2, the rubber lays on the top edge I9 of the cylinder H)in a completely relaxed state, or'under any degree of tension desireddepending to what extent the lower edge 25a of the. draw cam has beenpreviously lowered with respect to the top edge Ha of the rest cam H.

The rubber R in the sector R3,relaxed as a result of the needles beingraised by the clear-' ing cam IE to take the knitting yarn Y, retainsits relaxed condition and lays idly on the top I9 of the cylinder ID infront of the raised cylinder needles H and under the dial needles 2|,which at this stage are projected by their own projecting or clearingcams.

As the cylinder needles I l are again lowered by the stitch cam I8 topull the newly received knitting yarn Y through the stitches s thenhanging on the shanks of these needles, and the dial needles 2| arecoordinately retracted to take the knitting yarn Y and form it intoloops or stitches sl by drawing it through the stitches then hangingtherein, the relaxed rubber R, due to the curvature of the cylinder anddial and to the casting of the stitches and rubber over the points ofthe needles as the needles are lowered by the stitch cam l8, slidesinwardly over and from the top I!) of the cylinder III in an inlayingsector R4, onto those portions s2 of the knitting yarn Y which connectthe stitches s of the cylinder wales 10 with the stitches sl of the dialwales wl and lays in this position idly and relaxed clear around thecylinder to the feed for the yarn Y, whether it be the next feed on amultifeed machine or the same feed of a single feed machine as shown inFigs. 2 and 3.

In the meantime the cylinder needles have again been raised to the restposition by the incline Nb of the rest cam l4, this time outside therubber R which moves the rubber R into the in-laid position, in sectorR4, in the fabric between the wales w and wl. The dial needles at thesame time move out to a corresponding rest position between the cylinderneedles, above, the yarn R, and hold it against vertical displacementwhile the raised cylinder needles hold it against radial displacement.

The relaxed rubber ring lays on top of the stitch connectors s2 untilthe needles at the next feed of knitting yarn Y are operated and theneedles, after clearing, take the yarn and form it into the stitchesofthe next course, whereupon the connectors s2 of the new course areformed over the rubber R then lying in a relaxed state on the connectorss2 of the previous course, as clearly shown at Z in Fig. 3.

From the above it will be clear that by drawing the rubber down intothe, needle grooves to a greater or, lesser extent before it is laid inthe fabric a suflicient amount .of the rubber R is drawn from the supplyeach time by each 'needle to equalize or exceed the amount of elongationof the rubber created by the tension on the rubber resulting fromdrawing the rubber from its supply spool, etc., thus, if equalizingamounts are drawn by the needles the rubber circle or spiral convolutionthereof as laid in each course of stitches will coincide in diameterwith the knitting diameter or circumference of the knitting circle ofthe fabric, thus the knitting circle of the fabric will be retained.

If slightly less than equalizing amount of rubber are drawn by theneedles the diameter of the rubber ring will decrease somewhat below theknitting diameter of the fabric and the fabric circle will contractnormally as it would inherently in cases where no rubber is inlaid inthe fabric.

If excessive amounts of rubber R are drawn by the needles each time thediameter of each rubber ring or spiral convolution will exceed theknitting diameter of the fabric and the fabric will under suchconditions expand coursewise to a size greater than that of the knittingdiameter.

This condition, i. e. the coursewise expansion of the fabric, obviouslyis made possible by a walewise contraction when the pull of thedrawing-ofi. rolls or the drawing-off weight, which normally places thefabric under walewise tension to effect casting of the stitches from theneedles, is released. I v

The above description of the present invention has been confined to theknitting of ribbed fabrics however insofar at least as concerns thedrawing of the rubber from its supply by feeding it under the hooks of aset of knitting needles, lowering the needles to'draw the rubber intoloops or festoons in the needle grooves over the tops of the partitionsbetween the grooves or the equivalent thereof, and then raising theneedles successively to release the rubber in a relaxed state prior toincorporating the rubber in the fabric, the invention is equallyapplicable to machines for knitting plain, i. e. non-ribbed fabric on asingle bank of needles, the subsequent incorporation of the rubber intothe fabric as by actual knitting of the rubber itself into stitches orotherwise, in ways known to the art being merely coincidental to thepreparation of the rubber for such incorporation as disclosed above.

I claim:

1. The method of placing rubber yarn in knitted fabrics, which consistsin feeding the rubber under the hooks of the needles knitting the fabricwhile the needles are in tucking position,

successively lowering the needles to pull the rubher into the needlegrooves over the tops of the partitions between said grooves to measureand form the rubberinto loops therein and thereby draw the rubber from asupply thereof, and raising the needles successively at least to saidtucking position to release the rubber prior to incorporating the rubberin the fabric.

2. ,The method of placing rubber,yarn in knitted fabrics, which consistsin feeding the rubber under the hooks of the needles knitting the fabricwhile the needles are in tucking position, successively lowering theneedles to pull the rubber into the needle grooves over the tops of thepartitions between said grooves to measure and form the rubber intoloops therein and thereby draw the rubber from a supply thereof, holdingthe rubber in said loops in a plurality of said grooves,

and raising the needles successively at least to the rubber into loopstherein and thereby draw the rubber from a supply thereof, holding therubber in said loops in a plurality of said grooves,

raising theneedles successivelyat least to said tucking position torelease the rubber prior to incorporatingthe rubber in the fabric,raising the needles to clearing position, feeding knitting yarn to theraised needles with the relaxed rubber in front of the needles and belowthe latches thereof, and lowering the needles to draw the knittingthread through loops previously formed and hanging on the needles and tocast said loops and said rubber over the points of the needles to thebacks thereof.

4. The method of placing rubber yarn in knitted fabrics, which consistsin feeding the rubber under the hooks of the needles knitting the fabricwhile the needles are in tucking position, successively lowering theneedles to pull the rubber into the needle grooves over the tops of thepartitions between said grooves to measure and form the rubber intoloops therein and thereby draw the rubber from a supply thereof, holdingthe rubber in said loops in a plurality of said grooves, raising theneedles successively at least to said tucking position to release therubber prior to incorporating the rubber in the fabric, raising theneedle to clearing position, feeding knitting yarn to the raised needleswith the relaxed rubber in front of the needles and below the latchesthereof, lowering the needles to draw the knitting thread through loopspreviously formed and hanging on the needle and to cast said loops andsaid rubber over the points of the needles to the backs thereof andknitting stitches of a succeeding course into those cast over the pointsof said needles with said rubber to effect incorporation of the rubberin the fabric.

5. Th method of placing rubber yarn in knitted fabrics, which consistsin feeding the rubber under the hooks of the needles knitting the fabricwhile the needles are in tucking position, successively lowering theneedles to pull the rubber into the needle grooves over the tops of thepartitions between said grooves to measure and form the rubber intoloops therein and thereby draw the rubber from a supply thereof, holdingthe rubber in said loops in a plurality of said grooves, raising theneedles successively at least to said tucking position to release therubber prior to incorporating the rubber in the fabric, raising theneedle to clearing position, feeding knitting yarn to the raised needleswith the relaxed rubber in front of the needles and below the latchesthereof, lowering the needles to draw the knitting thread through loopspreviously formed and hanging on the needle and to cast said loops andsaid rubber over the points of the needles to the backs thereof andknitting stitches of a succeeding course by said needles into thestitches cast over the points of said needles with said rubber to eifectincorporation of the rubber in the fabric.

6. The method of placing rubber yarn in knitted fabrics, which consistsin feeding the rubber under the hooks of the needles knitting the fabricwhile the needles are in tucking position, successively lowering theneedles to pull the rubber into the needle grooves over the tops of thepartitions between said grooves to measure and form the rubber intoloops therein and thereby draw the rubber from a supply thereof, holdingthe rubber in said loops in a plurality of said grooves, raising theneedles successively at least to said tucking position to release therubber prior to incorporating the rubber in the fabric, raising theneedle to clearing position, feeding knitting yarn to the raised needleswith the relaxed rubber in front of the needles and below the latchesthereof, lowering the needles to draw the knitting thread through loopspreviously formed and hanging on the needle and to cast said loops andsaid rubber over the points of. the needles to the backs thereof,knitting stitches of a succeeding course by said needles into thestitches cast over the points of said needles with said rubber to effectincorporation of the rubber in the fabric and operating the needles todraw and hold the rubber prior to the knitting of the stitches ofeachcourse on and by said needles '7. The method ofplacing rubber yarn inknitted fabrics, which consists in successively forming the rubber intoa series of immediately adjacent elongated loops between relativelyfixed supports for the loops to measure and place the rubber undertension and draw said rubber from a suitablesupply prior to the feedingof the rubber to the knitting point of the fabric, varying the extentofelongation of said loops to control the length of the rubber relative tothe length of each course of stitches of the knitted fabric in which therubber is incorporated for establishing a predetermined tensionalrelationship between the rubber and the fabric coursewise thereof andreleasing said loops successively from one end of said series to relievethe rubber of said tension for delivering it in a substantially relaxedstate to said knitting point.

ROBERT E. DAVIS.

